(a) Technical Field of the Invention
The present invention is related to a magnetism controller, and more particularly, to one retrieves signals of changed magnetic filed created by displacement of a permanent magnet driven by rotation.
(b) Description of the Prior Art
Many peripherals including keyboard, mechanical roller mouse and up to present optical mouse or wireless mouse for the control and movement of cursor on screen in computer system have been consecutively introduced with their primary purposes of include cursor movement control, page scrolling and click control.
Whereas users were not satisfied with the slow and inconvenient use of the keyboard at the beginning in providing functions of an indicator, the mouse was invented. Up to now, mouse remains the most favored indicator to computer users. However, indicators either in earlier or current types are found with many limitations and defectives, such as:
1. Shorter service life. The scrolling metric control relates to mechanical movement since the achievement of scrolling metric control of the prior art relies upon a switch encoder.
2. Malfunction. Though the grating sensor is used for the rotation metric control of the latest indicator for longer service and more comfortable operation feel; the design on grating theories is vulnerable to inconsistent control.
3. Insufficient resolution. The design on grating theories for the rotation metric control of the latest indicator fails to improve its resolution, thus to prevent high-speed and precise scrolling.
4. Failing compact. Larger space consumed by the grating sensor device and its structure frustrates the application in the smaller indicator.
5. Higher production cost. Whereas the grating device dominates the primary control in the rotation metric control of the latest indicator, its assembly is comparatively complicated to increase the cost of the device, and the time and efforts needed for assembly.